Maize update John Morgan

Published 27 September 13

Farmers should be Dry Matter (DM) testing their maize crops now in order to set a harvest date, according to John Morgan from the Maize Growers Association.

The maize harvest for crops grown using plastic film is already underway in Devon, with these crops having hit the all-important 30-32% DM target for ensiling.

Conventionally drilled crops will not be far behind with DMs of 26% relatively common.  Maize, on average, ‘drys down’ at 2% per week, so those wanting to plan ahead should be DM testing their crops now in order to work out when to get going. 

When DM testing, it is worth remembering that the different crop parts contain very different amounts of moisture. The grain, for example, will be in the region of 70% DM when maize is fit to harvest whereas the stalk can be less than 20% DM.

To be sure of the overall plant DM, a full plant DM test is needed; this can be done in a conventional or microwave oven (link to MGA factsheet).  There is no substitute for this test. The chopped crops should be weighed fresh and for a second time when dry. To work out the average DM, divide the final dry weight of your maize sample by the original fresh weight and multiply this by 100.

Hitting the target DM will ensure the best compromise between silage quality, intake and storage.  Too wet at harvest and the silage will be acidic and less palatable.  Too dry, and while cows may eat more, avoiding secondary aerobic fermentation and silage waste can be very tricky. 

Great maize silage with DMs between 30 and 32%, starch levels of 30 to 35% and proteins levels of 9%, will provide a great base for winter feeding and should be the target. Crop DM testing is simple to do, and definitely worth it!